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Abstract:

A capacitive accelerometer includes a substrate and a first semiconductor
layer. The first semiconductor layer is disposed on the substrate and
includes a first mass, first and second support bases, first and second
elastic members, and first and second comb capacitor sets. The first and
second support bases are disposed at positions corresponding to first and
second axes respectively. The first elastic member is connected to the
first mass and the first support base in a manner of bending back and
forth perpendicular to the first axis. The second elastic member is
connected to the first mass and the second support base in a manner of
bending back and forth perpendicular to the second axis. The first and
second comb capacitor sets are disposed at positions corresponding to the
second and first axes respectively and connected to the first mass. The
first axis is perpendicular to the second axis.

Claims:

1. A capacitive accelerometer comprising: a substrate; and a first
semiconductor layer disposed on the substrate, the first semiconductor
layer comprising: a first mass; at least one first support base located
at least one side of the first mass corresponding to a first axis; a
first elastic member connected to the first mass and the first support
base in a manner of bending back and forth perpendicular to the first
axis, for making the first mass move elastically along the first axis
when a force is applied to the first mass in the first axis; at least one
first combo capacitor set connected to at least one side of the first
mass corresponding to a second axis; at least one second support base
located at least one side of the first mass corresponding to the second
axis; a second elastic member connected to the first mass and the second
support base in a manner of bending back and forth perpendicular to the
second axis, for making the first mass move elastically along the second
axis when a force is applied to the first mass in the second axis; and at
least one second combo capacitor set connected to at least one side of
the first mass corresponding to the first axis; wherein the first axis is
perpendicular to the second axis.

2. The capacitive accelerometer of claim 1, wherein the substrate has at
least one sensing electrode and the capacitive accelerometer further
comprises: a second semiconductor layer disposed on the substrate and
located at a side of the first second semiconductor layer, the second
semiconductor layer comprising: a second mass having a rotating shaft
along the first axis or the second axis for generating a sensing capacity
with the sensing electrode; and at least one third support base connected
to the rotating shaft for making the second mass asymmetrically disposed
above the sensing electrode; wherein the second mass is rotated relative
to the rotating shaft when a force is applied to the second mass in a
third axis, and the third axis is perpendicular to the first axis and the
second axis.

3. The capacitive accelerometer of claim 1, wherein the first
semiconductor layer comprises two first combo capacitor sets and each
first combo capacitor set comprises: a plurality of combo capacitor
boards extendedly formed from the first mass; and a plurality of fixed
combo capacitor boards fixed to the substrate, arranged alternatively
with the plurality of combo capacitor boards, and parallel to the
plurality of combo capacitor boards; wherein numbers of the combo
capacitor board and the fixed combo capacitor board on the two first
combo capacitor sets are different to each other.

4. The capacitive accelerometer of claim 1, wherein the first
semiconductor layer comprises two first support bases and two first
elastic members, each first elastic member is connected to the first mass
and the corresponding first support base in a manner of bending back and
forth perpendicular to the first axis, and the bending times of the two
first elastic members are different to each other.

5. A capacitive accelerometer comprising: a substrate; and a first
semiconductor layer disposed on the substrate, the first semiconductor
layer comprising: a first mass; at least two first support bases
respectively located at least one side of the first mass corresponding to
a first axis; two first elastic members respectively connected to the
first mass and the first support base in a manner of bending back and
forth parallel to the first axis, for making the first mass move
elastically along a second axis when a force is applied to the first mass
in the second axis; at least one first combo capacitor set connected to
at least one side of the first mass corresponding to the first axis; at
least two second support bases respectively located at least one side of
the first mass corresponding to the first axis; two second elastic
members respectively connected to the first mass and the corresponding
second support base in a manner of bending back and forth parallel to the
second axis, for making the first mass move elastically along the first
axis when a force is applied to the first mass in the first axis; and at
least one second combo capacitor set connected to at least one side of
the first mass corresponding to the second axis; wherein the bending
times of the two first elastic members are different to each other, and
the first axis is perpendicular to the second axis.

6. The capacitive accelerometer of claim 5, wherein the substrate has at
least one sensing electrode and the capacitive accelerometer further
comprises: a second semiconductor layer disposed on the substrate and
located at a side of the first second semiconductor layer, the second
semiconductor layer comprising: a second mass having a rotating shaft
along the first axis or the second axis for generating a sensing capacity
with the sensing electrode; and at least one third support base connected
to the rotating shaft for making the second mass asymmetrically disposed
above the sensing electrode; wherein the second mass is rotated relative
to the rotating shaft when a force is applied to the second mass in a
third axis, and the third axis is perpendicular to the first axis and the
second axis.

7. The capacitive accelerometer of claim 5, wherein the first
semiconductor layer comprises two first combo capacitor sets and each
first combo capacitor set comprises: a plurality of combo capacitor
boards extendedly formed from the first mass; and a plurality of fixed
combo capacitor boards fixed to the substrate, arranged alternatively
with the plurality of combo capacitor boards, and parallel to the
plurality of combo capacitor boards; wherein numbers of the combo
capacitor board and the fixed combo capacitor board on the two first
combo capacitor sets are different to each other.

8. A capacitive accelerometer comprising: a substrate; and a first
semiconductor layer disposed on the substrate, the first semiconductor
layer comprising: a first mass; at least one first support base located
at least one side of the first mass corresponding to a first axis; a
first elastic member having a first bending structure and a first step
structure, the first bending structure being connected to the first
support base in a manner of bending back and forth corresponding to the
first axis, the first step structure being connected between the first
mass and the first bending structure; at least one first combo capacitor
set connected to at least one side of the first mass corresponding to the
first axis; at least one second support base located at least one side of
the first mass corresponding to a second axis; a second elastic member
having a second bending structure and a second step structure, the second
bending structure being connected to the second support base in a manner
of bending back and forth corresponding to the second axis, the second
step structure being connected between the first mass and the second
bending structure; and at least one second combo capacitor set connected
to at least one side of the first mass corresponding to the second axis;
wherein the first axis is perpendicular to the second axis.

9. The capacitive accelerometer of claim 8, wherein a protruding block is
respectively formed on the first mass corresponding to the first step
structure and the second step structure.

10. The capacitive accelerometer of claim 8, wherein the substrate has at
least one sensing electrode and the capacitive accelerometer further
comprises: a second semiconductor layer disposed on the substrate and
located at a side of the first second semiconductor layer, the second
semiconductor layer comprising: a second mass having a rotating shaft
along the first axis or the second axis for generating a sensing capacity
with the sensing electrode; and at least one third support base connected
to the rotating shaft for making the second mass asymmetrically disposed
above the sensing electrode; wherein the second mass is rotated relative
to the rotating shaft when a force is applied to the second mass in a
third axis, and the third axis is perpendicular to the first axis and the
second axis.

11. The capacitive accelerometer of claim 8, wherein the first
semiconductor layer comprises two first combo capacitor sets and each
first combo capacitor set comprises: a plurality of combo capacitor
boards extendedly formed from the first mass; a plurality of fixed combo
capacitor boards fixed to the substrate, arranged alternatively with the
plurality of combo capacitor boards, and parallel to the plurality of
combo capacitor boards; wherein numbers of the combo capacitor board and
the fixed combo capacitor board on the two first combo capacitor sets are
different to each other.

12. The capacitive accelerometer of claim 8, wherein the first bending
structure is connected between the first support base and the first step
structure in a manner of bending back and forth perpendicular to the
first axis and the second bending structure is connected between the
second support base and the second step structure in a manner of bending
back and forth perpendicular to the second axis.

13. The capacitive accelerometer of claim 8, wherein the first bending
structure is connected between the first support base and the first step
structure in a manner of bending back and forth parallel to the first
axis, and the second bending structure is connected between the second
support base and the second step structure in a manner of bending back
and forth parallel to the second axis.

14. The capacitive accelerometer of claim 8, wherein the first
semiconductor layer comprises two first support bases and two first
elastic members, each first bending structure is connected between the
first mass and the corresponding first support base in a manner of
bending back and forth corresponding to the first axis, and the bending
times of the two first bending structures are different to each other.

15. A capacitive accelerometer comprising: a substrate; and a first
semiconductor layer disposed on the substrate, the first semiconductor
layer comprising: a first mass; at least two first combo capacitor sets
connected to least one side of the first mass corresponding to a first
axis; at least one first support base disposed between the two first
combo capacitor sets; a first elastic member connected between the first
mass and the first support base in a manner of bending back and forth
corresponding to the first axis; at least two second combo capacitor sets
connected to at least one side of the first mass corresponding to a
second axis; at least one second support base disposed between the two
second combo capacitor sets; and a second elastic member connected
between the first mass and the second support base in a manner of bending
back and forth corresponding to the second axis; wherein the first axis
is perpendicular to the second axis.

16. The capacitive accelerometer of claim 15, wherein the substrate has
at least one sensing electrode and the capacitive accelerometer further
comprises: a second semiconductor layer disposed on the substrate and
located at a side of the first second semiconductor layer, the second
semiconductor layer comprising: a second mass having a rotating shaft
along the first axis or the second axis for generating a sensing capacity
with the sensing electrode; and at least one third support base connected
to the rotating shaft for making the second mass asymmetrically disposed
above the sensing electrode; wherein the second mass is rotated relative
to the rotating shaft when a force is applied to the second mass in a
third axis, and the third axis is perpendicular to the first axis and the
second axis.

17. The capacitive accelerometer of claim 15, wherein the first
semiconductor layer comprises two first combo capacitor sets and each
first combo capacitor set comprises: a plurality of combo capacitor
boards extendedly formed from the first mass; a plurality of fixed combo
capacitor boards fixed to the substrate, arranged alternatively with the
plurality of combo capacitor boards, and parallel to the plurality of
combo capacitor boards; wherein numbers of the combo capacitor board and
the fixed combo capacitor board on the two first combo capacitor sets are
different to each other.

18. The capacitive accelerometer of claim 15, wherein the first elastic
member is connected between the first support base and the first mass in
a manner of bending back and forth perpendicular to the first axis, and
the second elastic member is connected between the second support base
and the second mass in a manner of bending back and forth perpendicular
to the second axis.

19. The capacitive accelerometer of claim 15, wherein the first elastic
member is connected between the first support base and the first mass in
a manner of bending back and forth parallel to the first axis, and the
second elastic member is connected between the second support base and
the second mass in a manner of bending back and forth parallel to the
second axis.

20. The capacitive accelerometer of claim 15, wherein the first
semiconductor layer comprises two first support bases and two first
elastic members, each first elastic member is connected between the first
mass and the corresponding first support base in a manner of bending back
and forth corresponding to the first axis, and the bending times of the
two first elastic members are different to each other.

Description:

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to an accelerometer, and more
specifically, to a capacitive accelerometer.

[0003] 2. Description of the Prior Art

[0004] In general, a conventional three-axis capacitive accelerometer
utilizes three independent masses with the related sensing electrode
components to sense accelerations in an X-axis, a Y-axis, and a Z-axis
independently. Although this design can prevent the linearity and
sensitivity of each sensing axis of the capacitive accelerometer from
being interfered by other sensing axes of the capacitive accelerometer,
this design needs to increase the overall volume of the capacitive
accelerometer for reducing mechanical noise received by the capacitive
accelerometer, so as to make the capacitive accelerometer oversized.
Thus, it should be a concern for a capacitive accelerometer to reduce its
overall volume and increase its sensitivity and linearity.

SUMMARY OF THE INVENTION

[0005] The present invention provides a capacitive accelerometer including
a substrate and a first semiconductor layer. The first semiconductor
layer is disposed on the substrate and includes a first mass, at least
one first support base, a first elastic member, at least one first combo
capacitor set, at least one second support base, a second elastic member,
and at least one second combo capacitor set. The first support base is
located at least one side of the first mass corresponding to a first
axis. The first elastic member is connected to the first mass and the
first support base in a manner of bending back and forth perpendicular to
the first axis, for making the first mass move elastically along the
first axis when a force is applied to the first mass in the first axis.
The first combo capacitor set is connected to at least one side of the
first mass corresponding to a second axis. The second support base is
located at least one side of the first mass corresponding to the second
axis. The second elastic member is connected to the first mass and the
second support base in a manner of bending back and forth perpendicular
to the second axis, for making the first mass move elastically along the
second axis when a force is applied to the first mass in the second axis.
The second combo capacitor set is connected to at least one side of the
first mass corresponding to the first axis. The first axis is
perpendicular to the second axis.

[0006] The present invention further provides a capacitive accelerometer
including a substrate and a first semiconductor layer. The first
semiconductor layer is disposed on the substrate and includes a first
mass, at least two first support bases, two first elastic members, at
least one first combo capacitor set, at least two second support bases,
two second elastic member, and at least one second combo capacitor set.
The two first support bases are respectively located at least one side of
the first mass corresponding to a first axis. The two first elastic
members are respectively connected to the first mass and the first
support base in a manner of bending back and forth parallel to the first
axis, for making the first mass move elastically along a second axis when
a force is applied to the first mass in the second axis. The first combo
capacitor set is connected to at least one side of the first mass
corresponding to the first axis. The two second support bases are
respectively located at least one side of the first mass corresponding to
the first axis. The two second elastic members are respectively connected
to the first mass and the corresponding second support base in a manner
of bending back and forth parallel to the second axis, for making the
first mass move elastically along the first axis when a force is applied
to the first mass in the first axis. The second combo capacitor set is
connected to at least one side of the first mass corresponding to the
second axis. The bending times of the two first elastic members are
different to each other, and the first axis is perpendicular to the
second axis.

[0007] The present invention further provides a capacitive accelerometer
including a substrate and a first semiconductor set. The first
semiconductor layer is disposed on the substrate and includes a first
mass, at least one first support base, a first elastic member, at least
one first combo capacitor set, at least one second support base, a second
elastic member, and at least one second combo capacitor set. The first
support base is located at least one side of the first mass corresponding
to a first axis. The first elastic member has a first bending structure
and a first step structure. The first bending structure is connected to
the first support base in a manner of bending back and forth
corresponding to the first axis. The first step structure is connected
between the first mass and the first bending structure. The first combo
capacitor set is connected to at least one side of the first mass
corresponding to the first axis. The second support base is located at
least one side of the first mass corresponding to a second axis. The
second elastic member has a second bending structure and a second step
structure. The second bending structure is connected to the second
support base in a manner of bending back and forth corresponding to the
second axis. The second step structure is connected between the first
mass and the second bending structure. The second combo capacitor set is
connected to at least one side of the first mass corresponding to the
second axis. The first axis is perpendicular to the second axis.

[0008] The present invention further provides a capacitive accelerometer
including a substrate and a first semiconductor layer. The first
semiconductor layer is disposed on the substrate and includes a first
mass, at least two first combo capacitor sets, at least one support base,
a first elastic member, at least one two second capacitor sets, at least
one second support base, and a second elastic member. The two first combo
capacitor sets are connected to least one side of the first mass
corresponding to a first axis. The first support base is disposed between
the two first combo capacitor sets. The first elastic member is connected
between the first mass and the first support base in a manner of bending
back and forth corresponding to the first axis. The two second combo
capacitor sets are connected to at least one side of the first mass
corresponding to a second axis. The second support base is disposed
between the two second combo capacitor sets. The second elastic member is
connected between the first mass and the second support base in a manner
of bending back and forth corresponding to the second axis. The first
axis is perpendicular to the second axis.

[0009] These and other objectives of the present invention will no doubt
become obvious to those of ordinary skill in the art after reading the
following detailed description of the preferred embodiment that is
illustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 is a top view of a capacitive accelerometer according to a
first embodiment of the present invention.

[0011] FIG. 2 is a side view of a second semiconductor layer in FIG. 1.

[0012] FIG. 3 is a top view of a capacitive accelerometer according to a
second embodiment of the present invention.

[0013] FIG. 4 is a top view of a capacitive accelerometer according to a
third embodiment of the present invention.

[0014] FIG. 5 is a top view of a capacitive accelerometer according to a
fourth embodiment of the present invention.

DETAILED DESCRIPTION

[0015] Please refer to FIG. 1, which is a top view of a capacitive
accelerometer 10 according to a first embodiment of the present
invention. As shown in FIG. 1, the capacitive accelerometer 10 includes a
substrate 12, a first semiconductor layer 14, and a second semiconductor
layer 16. The substrate 12 can be made of insulation material (e.g. glass
or ceramics) for holding the first semiconductor layer 14 and the second
semiconductor layer 16. The second semiconductor layer 16 is located at a
side of the first semiconductor layer 14. More detailed description for
the structural designs of the first semiconductor layer 14 and the second
semiconductor layer 16 is provided as follows.

[0016] The first semiconductor layer 14 includes a first mass 18, at least
one first support base 20, at least one first elastic member 22, at least
one first combo capacitor set 24, at least one second support base 26, at
least one second elastic member 28, and at least one second combo
capacitor set 30. In this embodiment, numbers of the first support base
20, the first elastic member 22, the first combo capacitor set 24, the
second support base 26, the second elastic member 28, and the second
combo capacitor set 30 are four respectively as shown in FIG. 1. The
first mass 18 can be made of semiconductor material (e.g. silicon
material).

[0017] In this embodiment, the first support base 20 is located two sides
of the first mass 18 corresponding to a first axis (i.e. an X-axis
direction as shown in FIG. 1) respectively. The second support base 26 is
located at two sides of the first mass 18 corresponding to a second axis
(i.e. a Y-axis direction as shown in FIG. 1) perpendicular to the first
axis respectively. The first elastic member 22 is connected between the
first mass 18 and the first support base 20 in a manner of bending back
and forth perpendicular to the first axis (as shown in FIG. 1), for
providing elastic force to make the first mass 18 move elastically along
the first axis when a force is applied to the first mass 18 in the first
axis. The second elastic member 28 is connected between the first mass 18
and the second support base 26 in a manner of bending back and forth
perpendicular to the second axis (as shown in FIG. 1), for providing
elastic force to make the first mass 18 move elastically along the second
axis when a force is applied to the first mass 18 in the second axis.

[0018] The first combo capacitor sets 24 are respectively connected to two
sides of the first mass 18 corresponding to the first axis. Each first
combo capacitor set 24 includes a plurality of combo capacitor boards 32
and a plurality of fixed combo capacitor boards 34. The plurality of
combo capacitor boards 32 is extendedly formed from the first mass 18.
The plurality of fixed combo capacitor boards 34 is fixed to the
substrate 12, arranged alternatively with the plurality of combo
capacitor boards 32, and parallel to the plurality of combo capacitor
boards 32. Accordingly, the first semiconductor layer 14 can sense the
acceleration of the first mass 18 in the second axis according to the
capacity variations of the first combo capacitor sets 24. As shown in
FIG. 1, in this embodiment, numbers of the combo capacitor board 32 and
the fixed combo capacitor board 34 on the two first combo capacitor sets
24 are different to each other, so as to increase the capacity variations
of the first combo capacitor sets 24. In such a manner, sensitivity of
the first semiconductor layer 14 in sensing the capacity variations of
the first combo capacitor sets 24 can be enhanced accordingly. The second
combo capacitor sets 30 are respectively connected to two sides of the
first mass 18 corresponding to the second axis. Accordingly, the first
semiconductor layer 14 can sense the acceleration of the first mass 18 in
the first axis according to the capacity variations of the second combo
capacitor sets 30. As for the capacity sensing design of the second combo
capacitor set 30, it can be reasoned according to the said description
for the first combo capacitor set 24, and the related description is
therefore omitted herein.

[0019] Next, please refer to FIG. 1 and FIG. 2. FIG. 2 is a side view of
the second semiconductor layer 16 in FIG. 1. As shown in FIG. 1 and FIG.
2, the substrate 12 has at least one sensing electrode 36 (two shown in
FIG. 2). The second semiconductor layer 16 includes a second mass 38 and
at least one third support base 40 (two shown in FIG. 2). In this
embodiment, the second mass 38 has a rotating shaft 42 along the first
axis. The third support base 40 is connected to the rotating shaft 42 for
making the second mass 38 asymmetrically disposed above the sensing
electrode 36, so as to generate a sensing capacity with the sensing
electrode 36. Accordingly, when a force is applied to the second mass 38
in a third axis (i.e. a z-axis direction as shown in FIG. 2), the second
mass 38 is rotated relative to the rotating shaft 42 so as to change the
sensing capacity between the second mass 38 and the sensing electrode 36.
In other words, the second semiconductor layer 16 can sense the
acceleration of the second mass 38 in the third axis according to the
capacity variations between the second mass 38 and the sensing electrode
36. The configuration that the second mass 38 is asymmetrically disposed
above the sensing electrode 36 is not limited to the design as shown in
FIG. 1. That is, the present invention can also adopt the design that the
second mass 38 has the rotating shaft 42 along the second axis instead,
so as to make the second mass 38 asymmetrically disposed above the
sensing electrode 36 along the first axis. As for which design is
utilized, it depends on the practical application of the capacitive
accelerometer 10.

[0020] In the said configuration, when a force is applied to the
capacitive accelerometer 10 to cause the acceleration of the capacitive
accelerometer 10 in the first axis, the first mass 18 moves elastically
toward the first axis. At this time, the distance between the combo
capacitor boards and the fixed combo capacitor boards on the second combo
capacitor set 30 varies with the said elastic movement of the first mass
18 in the first axis, so as to change the capacity of the second combo
capacitor set 30. Accordingly, the acceleration of the capacitive
accelerometer 10 in the first axis can be determined according to the
capacity variations of the second combo capacitor sets 30.

[0021] Similarly, when a force is applied to the capacitive accelerometer
10 to cause the acceleration of the capacitive accelerometer 10 in the
second axis, the first mass 18 moves elastically toward the second axis.
At this time, the distance between the combo capacitor boards 32 and the
fixed combo capacitor boards 34 on the first combo capacitor set 24
varies with the said elastic movement of the first mass 18 in the second
axis, so as to change the capacity of the first combo capacitor set 24.
Accordingly, the acceleration of the capacitive accelerometer 10 in the
second axis can be determined according to the capacity variations of the
first combo capacitor sets 24.

[0022] Furthermore, when a force is applied to the capacitive
accelerometer 10 to cause the acceleration of the capacitive
accelerometer 10 in the third axis, the second mass 38 rotates relative
to the rotating shaft 42 toward the third axis. At this time, the
distance between the second mass 38 and the sensing electrode 36 on the
substrate 12 varies with the said rotation of the second mass 38 in the
third axis, so as to change the capacity between the second mass 38 and
the sensing electrode 36. Accordingly, the acceleration of the capacitive
accelerometer 10 in the third axis can be determined according to the
capacity variations between the second mass 38 and the sensing electrode
36.

[0023] In summary, via assembly of the mass, the support bases, elastic
members, and the combo capacitor sets on the first semiconductor layer 14
and assembly of the sensing electrodes on the substrate and the
asymmetrically-rotatable mass on the second semiconductor layer 16, the
capacitive accelerometer 10 can have a three-axis acceleration sensing
function. To be noted, in this embodiment, as shown in FIG. 1, the
present invention utilizes the design that the first elastic member 22
bends back and forth perpendicular to the first axis to replace the prior
art design that the elastic member bends laterally between the mass and
the support base, so as to efficiently reduce the width of the first
semiconductor layer 14 in the first axis. Similarly, the present
invention utilizes the design that the second elastic member 28 bends
back and forth perpendicular to the second axis, to reduce the width of
the first semiconductor layer 14 in the second axis. Accordingly, the
purpose of reducing space occupied by the first semiconductor layer 14 in
the capacitive accelerometer 10 can be achieved for further decreasing
the overall volume of the capacitive accelerometer 10.

[0024] Next, please refer to FIG. 3, which is a top view of a capacitive
accelerometer 100 according to a second embodiment of the present
invention. Components both mentioned in the second embodiment and the
first embodiment represent components with similar functions or
structures. The major difference between the capacitive accelerometer 100
and the capacitive accelerometer 10 is the bending design of the elastic
member. As for the three-axis acceleration sensing design of the
capacitive accelerometer 100, it can be reasoned according to the first
embodiment and the related description is therefore omitted herein. As
shown in FIG. 3, the capacitive accelerometer 100 includes the substrate
12, a first semiconductor layer 102, and the second semiconductor layer
16. The first semiconductor layer 102 is disposed on the substrate 12 and
includes the first mass 18, at least two first support bases 20, at least
two first elastic members 104, at least one first combo capacitor set 24,
at least two second support bases 26, at least two second elastic members
106, and at least one second combo capacitor sets 30. In this embodiment,
numbers of the first support base 20, the first elastic member 104, the
first combo capacitor set 24, the second support base 26, the second
elastic member 106, and the second combo capacitor set 30 are four
respectively as shown in FIG. 3.

[0025] The first elastic member 104 is connected between the first mass 18
and the first support base 20 in a manner of bending back and forth
parallel to the first axis, for providing elastic force to make the first
mass 18 move elastically along the second axis when a force is applied to
the first mass 18 in the second axis. In this embodiment, the bending
times of the first elastic members 104 are different to each other. For
example, as shown in FIG. 3, the bending times of the first elastic
members 104 respectively located at the upper-left corner and the
upper-right corner of the first mass 18 are less than those located at
the down-left corner and the down-right corner of the first mass 18, so
that the movement of the first mass 18 in the second axis can be more
sensitive when a force is applied to the first mass 18 in the second
axis. Similarly, the second elastic member 106 is connected between the
first mass 18 and the second support base 26 in a manner of bending back
and forth parallel to the second axis, for providing elastic force to
make the first mass 18 move elastically along the first axis when a force
is applied to the first mass 18 in the first axis. The bending times of
the second elastic members 106 are also different to each other, so that
the movement of the first mass 18 in the first axis can be more sensitive
when a force is applied to the first mass 18 in the first axis. In such a
manner, via the said design that the bending times of the elastic members
are different to each other for making movement of the mass more
sensitive and smooth, sensing linearity and sensitivity of the capacitive
accelerometer 100 in the first axis and the second axis can be further
improved.

[0026] Next, please refer to FIG. 4, which is a top view of a capacitive
accelerometer 200 according to a third embodiment of the present
invention. Components both mentioned in the third embodiment and the
first embodiment represent components with similar functions or
structures. The major difference between the capacitive accelerometer 200
and the capacitive accelerometer 10 is the bending design of the elastic
member. As for the three-axis acceleration sensing design of the
capacitive accelerometer 200, it can be reasoned according to the first
embodiment and the related description is therefore omitted herein. As
shown in FIG. 4, the capacitive accelerometer 200 includes the substrate
12, a first semiconductor layer 202, and the second semiconductor layer
16. The first semiconductor layer 202 is disposed on the substrate 12 and
includes a first mass 204, at least one first support base 20, at least
one first elastic member 206, at least one first combo capacitor set 24,
at least one second support base 26, at least one second elastic members
208, and at least one second combo capacitor sets 30. In this embodiment,
numbers of the first support base 20, the first elastic member 206, the
first combo capacitor set 24, the second support base 26, the second
elastic member 208, and the second combo capacitor set 30 are four
respectively as shown in FIG. 4.

[0027] The first elastic member 104 has a first bending structure 210 and
a first step structure 212. The first bending structure 210 is connected
to the first support base 20 in a manner of bending back and forth
perpendicular to the first axis. The first step structure 212 is
connected between the first mass 204 and the first bending structure 212.
The second elastic member 208 has a second bending structure 214 and a
second step structure 216. The second bending structure 214 is connected
to the second support base 26 in a manner of bending back and forth
perpendicular to the second axis. The second step structure 216 is
connected between the first mass 204 and the second bending structure
214. In such a manner, compared with the prior art only utilizing the
bending structure to be connected to the support base and the mass, the
present invention utilizes the step structure (i.e. the first step
structure 212 and the second step structure 216) to be connected to the
bending structure (i.e. the first bending structure 210 and the second
bending structure 214) and the mass (i.e. the first mass 204) instead, so
as to reduce space occupied by the first elastic member 206 and the
second elastic member 208 on the first semiconductor layer 202.
Accordingly, a protruding block 218 can extend from the first mass 204
corresponding to the first step structure 212 and the second step
structure 216 respectively. That is, the overall weight of the first mass
204 can be increased without additionally increasing the overall volume
of the first semiconductor layer 202, so as to make movement of the first
mass 204 in the first axis and the second axis more sensitive. Thus,
sensing linearity and sensitivity of the capacitive accelerometer 200 in
the first axis and the second axis can be further improved.

[0028] It should be mentioned that the bending directions of the first
elastic member 206 and the second elastic member 208 are not limited to
the aforesaid embodiment. For example, the first bending structure 210 of
the first elastic member 206 can change to be connected to the first
support base 20 in a manner of bending back and forth parallel to the
first axis, and the second bending structure 214 of the second elastic
member 208 can correspondingly change to be connected to the second
support base 26 in a manner of bending back and forth parallel to the
second axis.

[0029] Finally, please refer to FIG. 5, which is a top view of a
capacitive accelerometer 300 according to a fourth embodiment of the
present invention. Components both mentioned in the fourth embodiment and
the first embodiment represent components with similar functions or
structures. The major difference between the capacitive accelerometer 300
and the capacitive accelerometer 10 is assembly of the support bases, the
elastic members, and the combo capacitor sets. As for the three-axis
acceleration sensing design of the capacitive accelerometer 300, it can
be reasoned according to the first embodiment and the related description
is therefore omitted herein. As shown in FIG. 5, the capacitive
accelerometer 300 includes the substrate 12, a first semiconductor layer
302, and the second semiconductor layer 16. The first semiconductor layer
302 is disposed on the substrate 12 and includes the first mass 18, at
least two first combo capacitor sets 304, at least one first support base
306, at least one first elastic member 308, at least two second combo
capacitor sets 310, at least one second support base 312, and at least
one second elastic member 314. In this embodiment, numbers of the first
combo capacitor set 304, the first support base 306, the first elastic
member 308, the second combo capacitor set 310, the second support base
312, and the second elastic member 314 are four respectively as shown in
FIG. 5.

[0030] The first combo capacitor set 304 is connected to two sides of the
first mass 18 corresponding to the first axis respectively. The first
support base 306 is disposed between the first combo capacitor sets 304.
The second combo capacitor set 310 is connected to two sides of the first
mass 18 corresponding to the second axis respectively. The second support
base 312 is disposed between the second combo capacitor sets 310.
Furthermore, the first elastic member 308 is connected between the first
mass 18 and the first support base 306 in a manner of bending back and
forth parallel to the first axis, and the second elastic member 314 is
connected between the first mass 18 and the second support base 312 in a
manner of bending back and forth parallel to the second axis.

[0031] In such a manner, via the said design that the elastic member is
disposed between the combo capacitor sets, movement of the first mass 18
in the first axis and the second axis can be more sensitive so as to
improve sensing linearity and sensitivity of the capacitive accelerometer
300 in the first axis and the second axis.

[0032] It should be mentioned that the design that the bending times of
the elastic members are different to each other and the design that
numbers of the combo capacitor board and the fixed capacitor board on the
combo capacitor sets are different to each other can be mutually applied
to the aforesaid embodiments, so as to make the structural design of the
capacitive accelerometer provided by the present invention more flexible.
Furthermore, the second semiconductor layer mentioned in the aforesaid
embodiments can be an omissible component for simplifying the structural
design of the capacitive accelerometer provided by the present invention.
In other words, the capacitive accelerometer provided by the present
invention can only have the first semiconductor layer for two-axis
acceleration sensing.

[0033] Compared with the prior art utilizing three independent masses with
the related sensing electrode components to sense accelerations in three
axes independently, the present invention utilizes the configuration that
the second semiconductor layer (for sensing the acceleration of the
capacitive accelerometer in the third axis) is located at a side of the
first semiconductor layer (for sensing the accelerations of the
capacitive accelerometer in the first axis and the second axis), to
prevent the capacitive accelerometer form being oversized. Furthermore,
via the design for making the bending times of the elastic members
different to each other or changing the bending directions of the elastic
members, the design for making numbers of the combo capacitor board and
the fixed combo capacitor board on the combo capacitor sets different to
each other, or the design for changing the configuration of the combo
capacitor sets and the elastic members, the present invention can further
reduce the overall volume of the capacitive accelerometer or improve
linearity and sensitivity of the capacitive accelerometer in the first
axis and the second axis.

[0034] Those skilled in the art will readily observe that numerous
modifications and alterations of the device and method may be made while
retaining the teachings of the invention. Accordingly, the above
disclosure should be construed as limited only by the metes and bounds of
the appended claims.